COMPOSITE LAYERS ON ST12T VALVE STEEL
Composite layers made of nitride and ceramic layers significantly increase hardness and resistance to abrasion and wear. The table presents typical hardness results obtained for the composite layer „nitride layer + composite layer” in ST12T steel and for the comparison of hardness of tool materials used in machining. According to these results, the application of composite layers on relatively soft valve material increases the hardness to above the hardest cemented carbide.
| Pos. | Material | Stan | Hardness HV0.05 |
| 1 | ST12T Steel | Improved (spr. w technicznym) | 290-310 |
| 2 | ST12T Steel | Improved + nitrided layer | 1000-1150 |
| 3 | ST12T Steel | Improved + composite layer | 2000-2400 |
| 4 | HSS Steel | Hardened | 820-900 |
| 5 | Cemented carbide | – | 1600-1800 |
The combined manufacturing process of the composite layer is based on the latest developments in surface engineering. It uses a non-equilibrium plasma environment of electrical breakdown in a vacuum for diffusion saturation and low-temperature synthesis of high melting metal compounds. It is very important to specialise the course of the stages and their automated control in order to maintain the continuity of the material and its bearing capacity.
Modified plasma nitriding (pulsed process) allows the formation of a nitride layer without a surface layer of nitrides or carbonitrides commonly referred to as „white layer”. It transforms into porous nitrogen ferrite during the synthesis stage of the compound, which thus loses its adhesion to the surface. The nitriding process is specifically targeted to achieve full nitrogen saturation of the surface, a layer with the correct thickness and hardness and at the same time without a “white” layer.
The stage of the synthesis of the high melting compound takes into account the specific properties of the substrate modified by nitriding and through material interfaces that adjust the properties of the matching materials. The stage is carried out at a temperature not higher than nitriding while maintaining tension and structural stability of the material.
Composite layers open a new stage in the battle against wear of machine and tool parts. They allow to significantly increase the lifetime of functional parts and assemblies as well as replacement of the materials with cheaper ones.
Composite layers are used for sheet metal dies (NC LV), hot stamping (WCL), forms and ejectors for PTS (WLC, WNL, structural steels).
Thanks to the installation of a new innovative system in the technological line, you will have access to a modern source of heat and electricity, additionally, by using absorption chillers it will be possible to supply chilled water to cooling or air conditioning systems.